/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.operation.buffer.validate;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryCollection;
import org.locationtech.jts.geom.LineSegment;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.geom.Polygon;
/**
* Computes the Euclidean distance (L2 metric) from a Point to a Geometry.
* Also computes two points which are separated by the distance.
*/
public class DistanceToPointFinder {
public DistanceToPointFinder() {
}
public static void computeDistance(Geometry geom, Coordinate pt, PointPairDistance ptDist)
{
if (geom instanceof LineString) {
computeDistance((LineString) geom, pt, ptDist);
}
else if (geom instanceof Polygon) {
computeDistance((Polygon) geom, pt, ptDist);
}
else if (geom instanceof GeometryCollection) {
GeometryCollection gc = (GeometryCollection) geom;
for (int i = 0; i < gc.getNumGeometries(); i++) {
Geometry g = gc.getGeometryN(i);
computeDistance(g, pt, ptDist);
}
}
else { // assume geom is Point
ptDist.setMinimum(geom.getCoordinate(), pt);
}
}
public static void computeDistance(LineString line, Coordinate pt, PointPairDistance ptDist)
{
Coordinate[] coords = line.getCoordinates();
LineSegment tempSegment = new LineSegment();
for (int i = 0; i < coords.length - 1; i++) {
tempSegment.setCoordinates(coords[i], coords[i + 1]);
// this is somewhat inefficient - could do better
Coordinate closestPt = tempSegment.closestPoint(pt);
ptDist.setMinimum(closestPt, pt);
}
}
public static void computeDistance(LineSegment segment, Coordinate pt, PointPairDistance ptDist)
{
Coordinate closestPt = segment.closestPoint(pt);
ptDist.setMinimum(closestPt, pt);
}
public static void computeDistance(Polygon poly, Coordinate pt, PointPairDistance ptDist)
{
computeDistance(poly.getExteriorRing(), pt, ptDist);
for (int i = 0; i < poly.getNumInteriorRing(); i++) {
computeDistance(poly.getInteriorRingN(i), pt, ptDist);
}
}
}